Tool handle



Sept. 29, 1936. J. OSGOOD TOOL HANDLE Filed July 18, 1934 757012: Oqyaod;

Patented Sept. 29, 1936 UNITED smrss PATENT orFie 8 Claims.

My invention relates to improvements in tool handles, and more particularly to handles for files or other tools in which movement lengthwise of the tool is required to manipulate the same.

In manipulating files and similar tools, it is necessary to grip the handle firmly in order to apply pressure to the object operated upon, and unless the handle is firmly gripped the hand will slide over the handle or the tool slip along the hand. This is particularly true when the handle is covered with oil or grease, or the hand of the operator is greasy, as invariably occurs in machine shops, or when the hand of the workman grasping the handle perspires.

It is the primary object of my invention to provide a tool which can be grasped with assurance that slipping movement relatively of the hand and tool will not take place, although only a fairly tight hold is taken of the handle.

Another object of my invention is to provide a tool handle in which special thumb and finger rests are provided which will permitthe handle to be grasped without cramping the hand, thus permitting a workman to use the tool for comparatively long periods of time without tiring or resulting in inconvenience.

Another object of my invention is to so form the tool handle that not only is movement of the tool within the hand prevented but the hand is allowed to assume a closing position on the handle approximating that occurring when partially closing the hand naturally without grasping any object, thus providing what I term the production of a balanced handle.

A still further object of my invention is to provide a tool in which thumb and finger depressions are provided in'spaced relation conforming to that of the thumb and third finger of a human handof normal size, and in which the finger depression is spaced from the butt or rear end portion of the tool handle so'that this butt or end portion will lie within the palm of the hand and bear against the ball of the thumb and the fleshy portion of the palm adjacent the ball of the thumb.

With the above and other objects to appear hereinafter, my invention consists in the novel features ofconstruction and formation of tool handle hereinafter described and more particularly pointed out in the subjoined claims.

In the drawing: r

Fig. 1 is a side elevation of a tool handle constructedin accordance with my invention.

Fig. 2, is as similar view showing the same grasped by a hand and illustrating the thumb within a-longitudinally-trending thumb depres sion and the third finger of the hand within a transversely-trending finger depression, also showing the rear end or butt of the handle lying against the ball of the thumb and the fleshy portion of the palm and a portion of the ball of the thumb entered partly in said finger depression.

Fig. 3 is a diagrammatic view showing the outline of the tool handle and the positions of the thumb and a finger of a hand in the act of grasping the handle.

Files and other tools usually have tangs adapted to ,be driven into a tool handle of the kind to which this invention relates, and the handle herein shown and described is particularly adapted for attachment to a file, although it may be applied to other tools in which a longitudinal movement is necessary in the use of the tool. Handles of files used in machine shops become quickly impregnated with oil or grease, and the workmen using the files oftentimes have greasy hands, or the hands perspire from grasping the handle, even though otherwise unsoiled, which make it extremely difiicult to operate a file without resorting to the use of a tiresome grip of suflicient force to prevent sliding of the tool handle within the hand and to enable the proper pressure to be applied to the work-piece or other object to be filed. Moreover, grasping a handle of conventional form for any length of time with the necessary force to perform effective work, retards circulation and causes the finger tips to become numb, thus necessitating relaxation of the hand from time to time to bring the hand to its natural condition. This results in loss of time, retards production and quickly tires the workmen.

To prevent such action and lessen the force necessary to properly grip the handle, I provide a handle which is preferably constructed of wood in the usual way and equipped with any suitable ferrule 4 at its forward end, the handle being provided with the usual tank hole 5 extending axially inwardly from its forward end, as shown by dotted lines at Fig. 3, into which hole the tang of a file or other tool is forced so as to securely fasten the handle to the tool.

On the surface of the handle I providea longitudinal concaved depression 5 in spaced relation to the ferrule 4 at the forward end of the handle, and the portion between said longitudinal depression-which I term a thumb rest'or depressionand the ferrule, an enlargement 1 is formed. The longitudinal depression 6 approximates in length and in formation the inner superficial surface of the thumb of a hand of average size, by which I mean any hand not abnormally large or small, and with this in view the handle is enlarged in rear of said depression, as at 8; this enlargement being preferably of greater diameter than the enlargement I. In rear of the enlargement a transverse finger depression or rest 9 is formed, the depression being spaced from the rear or butt end Ill of the-handle while that portion of the handle between said butt end 10 and the transverse depression 9 is enlarged to approximately the size of the enlargement 8.

The forward portion 1 I of the concaved thumb depression 5 merges into the enlargement 1- of the handle, and this enlargement and the adjacent merging portion of said depression forms a stop or abutment for the thumb, the thumb depressionbeing extended toward the enlargement. 8.in more gradually sloping relation than the portion of the depression adjacent the enlargement 1 so that a close approximation to the shape of the thumb is assured by the particular longitudinal. curvature of this depression. The thumb depression is therefore so formed that its smallest diameter is forward of its longitudinal center. That por tion of the thumb adjacent theball thereof rests comfortably upon the enlargement 8, asindicated at l2, Fig. 3, and the end portion of the thumb abuts firmly against the outwardly and forwardly inclined portion of the handle at the front of the thumb depression.

While I have referred to a longitudinal thumb depression and a transverse finger depression, I do not wish to be limited by such terms except in so far as longitudinal is intended to mean truly longitudinally or in a direction more close- 13; approaching the longitudinal than the transverse, While under the term transversely I mean truly transversely or in a direction more closely approaching the transverse than the longitudinal. For this reason, and for the reason that I desire to make it convenient to grasp the handle regardless of the position of the same when taken up by the workman, the longitudinally-concaved thumb depression is preferably extended completely around the handle and the transversely-trending depression is also by preference extended completely around the handle. Thus, it will be apparent that while one workman may grasp a the handle by having his thumb naturally in truly longitudinal position, another may have the thumb at a slight angle to the longitudinal. The forming of the longitudinal thumb groove in the preferred form will, therefore, accommodate any natural position of the thumb of a workman, and this is also true of the finger of the hand which is adapted to enter the transverse finger depression or groove, particularly since the natural position of the third finger, which is intended for contact with the finger depression or groove, is at a slight angle to the transverse when the hand is closed or partially closed. Consequently, by continuing this transverse groove around the handle a natural and easy rest is provided for this finger, regardless of its inclination to a line extending transversely through the handle.

By placing the third finger of the hand within the finger depression or groove, the elevated enlarged portions of the handle at opposite sides of the finger depression or groove form stops or abutments, so that the tendency of the handle slipping within the hand in either direction is checked, and since a file'ha's its most efiective action during a forward stroke of the same, the thumb resting against the enlargement or abutment 1 will prevent movement of the handle in a direction opposite that of the. file, and even though the handle is oily and slippery and the hand of the user is perspiring or greasy, a firm hold is assured on the handle without gripping force being applied even approximating that necessary with an ordinary handle.

It is to be noted that when grasping the handle, the end of the third finger is longitudinally offset with respect to the thumb, and consequently' where the thumb and finger depressions are not continued around the handle, such a relation between the thumb and finger depressions will be found necessary, or at least desirable. I, however, prefer to' form both the thumb and finger depressions circumferentially around the handle sothat it is not necessary for the workman to turn the handle when taking it up for use in order to position the thumb and finger in their respective depressions.

I particularly desire to. stress the fact that when the handle is grasped and the thumb rests in the thumb depression and the end of thethird finger is positioned within the transverse. finger depression, the index and middle fingers lie in contact with the gradually increasing diameter of the rear portion of the thumb depression and with the enlargement 8 which gradually merges into the thumb depression and the transverse finger depression. In consequence of this the said two fingers engage smooth surfaces of the handle, and the handle is therefore not provided with special grooves for each of these fingers, which results in a region being provided for contact of these fingers that will enable the handle to be conveniently grasped by any average or normal size hand while retaining the relationship between the transverse finger depression and the thumb depression and its abutment to naturally receive the end of the third finger and the thumb, respectively, of any hand not abnormally large or small. The smooth portion of the handle between the smallest diameter of the thumb depression and the transverse finger depression therefore provides a region which will be convenient to be grasped or serve as a rest for the index and middle fingers of any average sized hand It is to be noted that the relation between the thumb depression and the finger depression is such that the spacing of these parts is approximately that of the natural positions of the two hand digits adapted to enter them; also that the finger depression is so spaced from the butt or inner end of the handle that the inner end portion of the handle lies within the palm of the hand when grasped by the latter, with the butt or end bearing against the ball of the thumb and the fleshy portion of the palm; thus also preventing inward movement of the handle during the act of filing.

It may also be noted that relative movement of the hand" and handle is further prevented by reason of the fact that the soft inner portion of the ball of the thumb will partially enter the finger depression when the latter is continued circumferentially around the handle- The transversely-disposed finger depression is comparatively wide so that it will easily receive the end portion of the third finger of handsof various sizes regardless of the inclination to the transversethat they may be 'positionedin, and although it is comparatively wide with respect to the transverse dimension of a'finger it is comparatively narrow with respect to the corresponding dimension of the circumferentially longitudinally-trending concaved thumb depression forward thereof. I I

The preferred construction of my improved handle furnishes what I term a balanced handle, for the reason' that when. the thumb and finger depressions "are circumferentially formed in the handle, the weight is exactly the same at either side of a plane passing longitudinally through the handle.

By reason of the fact that this improved handle accommodates the hand in a natural partially closed position without applying strain to one finger more than anotherior, as it may be expressed, to one portion of the hand more than another, the balanced grip of the handle is assured. This is due to the fact that when grasping the improved handle, tension or strain on the muscles of the fingers of the hand are equalized, and this is especially true of the strain applied to the muscles of the thumb and third finger. The first finger may, if desired, be relaxed or relieved of strain, but if made to grasp the handle the muscles of this finger will conform to the strain applied to the remaining fingers. I desire also to call attention to the fact that the veins and nerves in the wrist and forearm, as well as those in the several digits of the hand, will be under equal tension, and the possibility of numbing of the finger tips is therefore entirely eliminated. It will be apparent therefore that a balanced grip is assured and considerably less gripping strain of the hand required to do effective work than with the conventional type of handle.

The user can therefore use a file over long periods of time with less strain and effort, without cramping the hand or becoming quickly tired by reason of an unnatural grip on the handle; and I particularly stress the fact that the handle is so formed that when the hand grips the same the positions of the several digits of the hand approach those that would be assumed upon the natural partial closing of a hand without attempting to grasp an object, and this results in considerable less strain being applied to'the muscles and other parts of the hand and forearm which come into play when closing the hand or exerting force under a gripping action.

Having described my invention, what I claim 1. A tool handle having a longitudinally-trending thumb depression continued circumferentially around the handle, said depression being concaved longitudinally and having its greatest depth forward of its longitudinal center, a transverse finger depression extending circumferentially around the handle in rear of said thumb depression, the portion of the handle between said thumb depression and the forward end of the handle being enlarged to serve as an abutment for a thumb while the portion between said thumb depression and said finger depression is of enlarged diameter to form an abutment forward of said finger depression, the rear end of said handle being enlarged to form an abutment in the rear of said depression.

2. A tool handle comprising an elongated body of approximately circular formation in cross sectional shape having a circumferential thumb depression near its forward end, a circumferential abutment adjacent said end into which said thumb depression merges and a circumferential finger depression in rear of said thumb depression adapted to receive a finger of the hand when grasping the handle and having said finger in longitudinal offset relation to the thumb positioned in said thumb depression.

' 3. A handle for files and other tools adapted for reciprocable movement having a longitudinally trending thumb depression extending around the handle and spaced from the forward end of the latter, an abutment for the thumb extending around the handle between said forward end and said thumb depressiomand a transversely trending finger depression also extending around said handle in a plane in rear of said thumb depression adapted to receive the end of the third finger of the hand when grasping the handle and having said finger in longitudinal offset relation to the end of the thumb positioned in said longitudinally trending thumb depression, the grasping of the handle by the hand assuring a firm unstrained grip preventing lengthwise movement of the handle in the hand during filing or other action applying strain to the handle in the direction of its axis.

4. A tool handle bulged outwardly near its for- Ward end and having a comparatively large transversely-extended concaved portion in rear of said outwardly-bulged portion to receive the thumb of the hand when positioned obliquely to the axis of the handle, the front end of said concaved portion merging into said outwardlybulged portion and the rear end thereof merging into a transverse enlargement, a. comparatively narrow transversely-extended concaved portion in rear of said enlargement and merging into the latter, said last-mentioned transversely-extended concaved portion being of greater diameter than the smallest diameter of said firstmentioned transversely-extended concaved portion, and an enlarged portion in rear of said comparatively narrow transversely-extended concaved portion terminating a short distance from the latter and adapted to be positioned within the palm of a hand when grasping the handle with the rear end bearing against the ball of the thumb and the fleshier portion of the palm of the hand while the end of the third finger is entered in said narrow transversely-extended concaved portion and the thumb is positioned within the said comparatively large transversely-extended concaved portion in contact with said outwardlybulged portion.

5. A tool handle having a thumb depression and a finger depression, both extending around the handle and adapted to respectively receive the thumb and a selected finger of any hand of normal size when grasping the handle, a portion intermediate said two depressions serving as a contact region for other fingers of the hand, said contact region being comparatively smooth and. ungrooved to enable the fingers of different sized hands to contact the same in a natural manner, the relative arrangement of said thumb and finger depressions being such that upon grasping the handle muscle strain throughout the hand is equalized.

6. A tool handle having a thumb depression and a finger depression, both extending around the handle and adapted to respectively receive the thumb and third finger of any hand of normal size when grasping the handle, a portion intermediate said two depressions serving as a contact region for the index and middle fingers of the hand, said contact region being comparatively smooth and ungrooved to enable the last-mentioned fingers or different sized hands to contact the same in a natural manner, the relative arrangement of said thumb and finger depressions being such that upon grasping the handle, strain on the nerves and other parts of the hand normally strained upon a natural closing of the hand is equalized.

7. A tool handle having a thumb depression extending completely around the same near its outer end, a thumb abutment forward of and merging into said thumb depression and extending completely around the handle, a finger depression spaced from said thumb depression and extending completely around the handle, a region between said depressions extending completely around the handle and merging into both depressions whereby the handle may be grasped irrespective of its rotative position with assurance that a comfortable grip will be provided for the hand. z

8. A tool handle 'for. files and other tools adapted for. reciprocable movement having a depression extending around the handle for reception of the thumb of a' hand, an abutment for the end of the thumb adjacent said. depres- 'sion and extending around the handle and a finger. depression also extending around said handle in a plane in rear of said thumb depression adapted to receive the end of a finger of a hand when grasping the handl'e,*the grasping of the handle by the hand assuring a firm unstrained grip preventing lengthwise movement of the handle in the hand during filing or other action applying strain to the handle in the direction of its axis. V

JOHN L. OSGOOD. 

